Coxiella manipulation of cholesterol in the intracellular niche

项目摘要/摘要 伯氏柯克斯体是人类Q热的病原体，Q热是一种人畜共患疾病，可导致虚弱的流感- 如急性病例中的疾病，或慢性患者中危及生命的心内膜炎。Q热病患者在场 几乎没有明显的临床特征，慢性病至少需要18个月的抗生素 治疗，突出了对新疗法的需要。柯克斯体是一种专性细胞内病原体，它存活了下来 在一个巨大的溶酶体样寄生虫液泡内，它是细菌复制所必需的，并保护 细菌来自宿主的免疫反应。柯克斯体寄生空泡通过 与宿主内噬小体和自噬小体的异型融合，这一过程也将胆固醇输送到 CPV膜。我们最近确定，宿主胆固醇在CPV中的积累对 细菌，并假设柯克斯体必须消耗CPV胆固醇才能在宿主细胞内生存。 这个应用程序的目标是测试我们的假设，即柯克斯体使用两种不同的机制来 操纵CPV胆固醇。目标1将测试膜接触部位在胆固醇转移中的作用 CPV和寄主内质网。目标2将确定推测的柯克斯氏菌类固醇的作用 还原酶在修饰CPV胆固醇中的作用。在这些研究的结论中，我们将阐明 柯克斯体通过操纵宿主胆固醇来维持细菌生存的最佳微环境。

PROJECT SUMMARY/ABSTRACT Coxiella burnetii is the causative agent of human Q fever, a zoonotic disease that can cause a debiliting, flu- like illness in acute cases, or a life-threatening endocarditis in chronic patients. Q fever patients present with few distinguishing clinical features, and chronic disease requires a minimum of 18 months of antibiotic treatment, highlighting the need for new therapeutics. An obligate intracellular pathogen, Coxiella survives inside a large, lysosome-like parasitophorous vacuole that is essential for bacterial replication and protects the bacteria from the host immune response. The Coxiella parasitophorous vacuole (CPV) forms through heterotypic fusion with host endosomes and autophagosomes, a process which also delivers cholesterol to the CPV membrane. We recently determined that accumulation of host cholesterol in the CPV is toxic to the bacteria, and hypothesize that Coxiella must deplete CPV cholesterol in order to survive within the host cell. The objective of this application is to test our hypothesis that Coxiella uses two distinct mechanisms to manipulate CPV cholesterol. Aim 1 will test the role of membrane contact sites in cholesterol transfer between the CPV and the host endoplasmic reticulum. Aim 2 will determine the role of putative Coxiella sterol reductases in modifying CPV cholesterol. At the conclusion of these studies, we will have elucidated how Coxiella manipulates host cholesterol to maintain the optimal microenvironment for bacterial surivival.